Spark plug



Patented Feb. 27, i923.

.Unirse lerares f @1,446,853 ,PTE

JOSEPH M. viwr'eKniarmN, or Sr. LOUIS, MISSOURI, AssIGNoR. er` DIRECT AND MESNE ASSIGNMENTS, orONE-HALF To Mauna I.. IVICKERNAN AND ONE-rimerl TO-'Iioo'rsii1v I e. wOLLBRINOm BOTH or sfr, tours,` aIIssoUaI.V

Y SPARK PLUG. y

` Application mea. FebruaryeS, 1919.y serial nojafzalafi.V

To 'all whom t may concern:

'Be it Vknown that I, JOSEPH M. MOKEP.-

Y NAN, a citizen of the UnitedStates, residing at St. Louis, in theState of, li/lissouri,`

provements in Spark Plugs; and'I do have invented certain new and useful Imhereby` declare the following to be afull, clear, and exact description ofthe invent1on, such as Will enable others skilledin the art to Which'it appertains to make and use the Same. 5 Y, rT his invention relates to a spark plug'and yparticularlyV to ai construction wherein a vspa-'rk gapisproduced Within an air tight lchamber formed in the plug.

The iinvention Vhas 'for' an object to pro'-y Iduce a novel and improvedy construction of the' cooperating: members Jfor effecting the spark gap andinvolvesthe provision of a ventilating chamber surrounding the core insulated and completely sealed from the spark gap chamber and also from theeleetrodes at the inner end of the plug.

A 'further objectfoff of vthe spark gap members vwherein the i spindle4 telescopes the Opposite electrode to eectvan automatic adjustment and avoid Acontactbetween the spark gap ,points Vso that lthe latter is constant and not liable ae "cidental'displacement.' y Y I Another and further obliee't and advantage .of the invention isgtoA provide al spark gap `chamber formed thevdepending portion of the capwhiehis provide/d :with a 'conical aperture Vto receive the -eone shaped endfof the corecarrying the' electrode member coni- Figure 4 a similar vievv oftheadjustable "s arkgap'cup and y l PFigure 5 .a'detail perspective of thefgasket `ring."" 'I' Like numeralsjrefer tO-like parts 1n the severalgures ofthe 'd1 a\`v1ngs.` 4 The numeral; 10l designates Ithe shell or the invention is toy provide Va novel and'improved construction body ofvthespark-plug vvhi'ehfmaylbe of any desired construction ,and configuration and is provided at its lower end With an exteriorly threaded portion 11to enter the engine casingand with a sparkV pointf or bladefl2. The upper portion of fthisfshell 1s provided With an -angularrwrenchfface13 and interiorly threaded as at yll'tovgreceive NrDFrieE;

the lower threaded'portion 15v of the bush. lj

ing or'eap casing 16, Whichis also provided With a VWrench face 17 VVithin'theV body of the shell 10 ay Ventilating chamber 18 is yformedwhichsurrounds 'the body .of the core or lnsulating memberi'g19-"disposedWith! in the Shen.' :This Chamber reformed .with

tWo or more air inlets 20 'fjto' draw oifq'the lsuperheated air and permit'circulation ,of I

cool air around'the core'klwhich ina-y be formed of any desired insulating material, l

Such as Porcelain O' Other Vtreous-inatter; Y

-The shell 1Q is also formed 'with a shoulder or seat 21 at the'bottom of 'the Chamber 18 upon which `.thegasket or packing ringl 22 is disposed, and the body lof the c'orefl) is provided- Withaslioulder 23 adaptedjto I rest upon this ring so as tof. effect an abso- The gasket 2211s preferably-6taspentiQa-f y "struction comprlsingthe jUl'shaped inetal l ife 7 1 A lutelyV gastight` seal betvveen "the core' ,and

kwhen 'underl con`r1pf ressionthe"l packingjis This .packing 22" is duplicated atthef-ulp- 'pressed by the inner threadedend jof the bushing' or cap :casing @16. 'This 4,bushing A adapted to receive thecapisulator'26which is, suitably secured'jwithinfthe 'upper cyli'ii'-V drical portion thereof, by a 'bindingffor-i.

'tion 2810iV thecap insulator is .formed with afeonical` aperture whichlcompletely y gulf-. rounds and encloses the upperportion29fof Vthey core V:from which theeleetrode'or spark v point -BOeXtends'.V Thefopposite end "Of-this electrode projects `f-romthe' lower portion of i the core inthe usual mannerandprovides a sparking point 51'disposedoppositefandfin`iv spaced relation to thetpoint 12;

,- ',Mounted in an aperture y'central of Vthe 'cap .Y

insulator 26is the spark gap spindle 32 suitably threaded for purposes to be hereinafter described and at the lower end of this spindle a-cup 33 is formed Which telescopes the spark point 3l and for that purpose isvpi'ovided With an interior recess tapering outwardly at its open endas shown at 34. ThisV spindle is also formed Witha shoulder 35 to abut against the under face oi the cap recess and is adapted to be adjusted by 'the nut 36 threaded upon the stein 32 to contact Vwith tlie'ujpperfface of the cap. F or the purpose of binding electric conductor Vin contact with this lthe usual binding mit is provided' upon the spindle-32. Y The constru'ctio'n and operation of the vention-'Will be apparent from the foregoing description and it will beo'bserved that the 'locatinfo-f the Ventilating chamber between the upper andv lower gaskets to surround the central "portion of the core or insulator provides meansf'or Witlidr'awingvv the superheated air and permitting circulation ot' cool air aroundv lthe porcelain Without dalger ot said air gaining access to the ark gap chamber occupied by' the ends oil, the electrodes. The ventj aperturesjl() permit any gas' escaping past the lower gasket/to pass 011tfmfl not' force its passage beyond the UPP?? gasket to enter the vspark gapy chamhelwhere an eXplQsQnWeuld Otherwise. 0ccur and result in' the destructionof Vthev plug. Even the most*perfect*,construction of gasket will at'sometime'leak and' the provision oft/.helse vent holesV absolutely.prevents the gas being forced' intoV the spark gap chamu be!" even `under the compression pressure from the engine.V This-is an important feature as no plug with a spark gap chamber eanoperatesuccessfullyif gas isfallowed to @aber :and esplode therein what the prim-i- /sioifi ofY a Ventilating cli-amber vintliis: inven-v tioliyellers'the' plugboth safe and efficient. l Experiments have demonstrated that the spark gap chai'nber must be absolutely air tight aiifd iii"`lf`aet a. yacuum Vis produced Ltherein as the spark consumes the nitrogen and oxygen in theair present in the chamber lwhich"requires from 5,000 te 157000 laddiposedto atmosphericpressure and this addedv to the Vrequired'voltage necessary to produce the spark in the cylinder or combustion chamber .under compression is a severe strain lupon'the coils and. a. greater drain ...upon the vbatteries 'which :frequently results Vinshort circuitiiig the coils/and destroying the battery. partial vacuum is produced Within vthe*airtight chamber due to theconsiiinption of certain elements' of the airby the are produeedbetweenthe adjacent Vends .of theelectrodes so thatthereis: little if any Aresistance tothe formation ofthel spark and the extra consumption of current is negligi- V ble. f The use of the vent holes in the veiitila tionalV volts-tov make thisarc Where it is eX- I tion between the gaskets permits the success-ful application of an air tight spark gap chamber as the entrance of gas thereto is absolutely prevented. The particular eonstruci tion of gasket herein shown vis specially adapted for use inthis construction of spark plug as it is held by the retainerperma'- nently in place so that the plugv may be dis assembled Without disturbing the gasketv seating and theser gasket members are not liable to be misplaced or overlooked in reassembling the plug.

It Will also' be seen that` thev spark gapfpre- A sented in the presentl invention' o'ceursenztirely Within the insulated' vchamber formed by the recessed cap insulator positioned over the upper end of core 29 carrying the eleccore electrode extending into theptapei'jing recess or the spindle orcesjthe Ycurrentto VThis forms Y an jumpy from the sides ofthe oavityin the spindleto the electrode of the core.- VThis part being enclosed in an' absolutely air tight insulated chamber a vacuum is'soonestab lished and owing 'to the absence :of artiiiosV i pheric `resistance a greatly vintensii'ed 'spark results. Sucha spark tends to highlyheat the insulated core Which becomes l s elficient asthe temperature/rises, andth''egntil lating chamber therefore v cooperates `with the telescopic spark ,gap to maintain' 'the fcore at a.- proper temperature. ,Well als pr@- vent the passage' of gasjinto rthegsparlr chamber. e Y v l n 'A particular construction and arrangement of the vseveral@members ot this;r Spark plug. have been shown and describedbi the iio'.

invention is not specificallyfconiined thereto as changes may Ybe made therein Within' the scope of therappended' claims@ `lVhat I Vclaim is:

l'. In a spark j lugjfa slielh an insulating `core positioned tliierjein74 an electrode in said core and'projectling beyond the upper end thereof, a bushing removablypositioned on the upper end .ofthe shell; a-fcapV vere beinsulator carried by saidbushinov ith ing an air-tight chamber formed bet insulating core and said cap insulat, anelectrode carried bysaid ,cap iiifu-lator and provided at its'end? Withinthe air-tight chamber-,With a recess is adajjfitejd.toire-V ceive the adjacent end lof the electrodecar-Y ried by the iiisulatingrcore.

2. In a spark plug, a shell,

an insulating core positioned therein, an electrode seated in said core 'and projecting beyond the 'up- 12oY i iso? U `core mounted thereon, an electrode eXtendper end thereof, a bushing removably positioned on the upper end of the shell, a lcap insulator carried by said bushing, there being an air-tight chamber vformed between the insulating core and saidfcap insulator, and an electrode adjustably carried by the cap insulator, the end ofsaid electrode Within the air-tight chamber being constructed" so as to partially surround the upwardly projecting end of the electrode carried by said insulating core.

3.'In a spark plug, a shell, an insulating ing through and above said. core, a bushing 

